I have a firewire hard drive connected to my Mac Mini that is wired over the network on a gigabit ethernet. My Macbook Pro is taking FOREVER to backup time machine. Any ideas?

you just have to give it a little.
The estimation time will change dramatically.
Kind of off topic but did anyone notice in Mountain Lion you can now do Time Machine backups to multiple drives? My main backup was to a Time Capsule which is ridiculously slow since I use wifi, but I saw you can connect a drive directly to the Mac and set it up as a 2nd backup disk. So now it alternates between the two.
Redundancy is pointless if all the drives are located in the same place and your house burns down. I'm too lazy to deal with scheduled full disk backups but with the new multiple drive feature I can now swap a Time Machine drive into a safety deposit box every six months while also being able to maintain a local active TM. So it's a great secret feature to Time Machine for software that really has been neglected by Apple.yeah, when I picked a different drive it asked if I want to replace it or add it. Cool new feature for triple redundancy.
Redundancy is pointless if all the drives are located in the same place and your house burns down. I'm too lazy to deal with scheduled full disk backups but with the new multiple drive feature I can now swap a Time Machine drive into a safety deposit box every six months while also being able to maintain a local active TM. So it's a great secret feature to Time Machine for software that really has been neglected by Apple.
oh yeah, im using thunderbolt ethernet adapter, and I just transfered an 800MB file to that drive to see if its the network and it took about 30 secs to complete.
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it suddenly started moving.
Did you update to latest version of Lion or ML? It was a software bug which Apple fixed in the last update a couple of weeks ago.
in order for Time Machine backups to work as you presume, everything must be indexed using Spotlight. If the little Spotlight has a "dot" in the middle while it is backing up, it is busy. You can verify this using Activity Monitor.
The first complete backup is thus, slow, for anyone. That is, compared to the incrementals which happen afterwards.
And Gig Ethernet is slow for this, compared to locally attached storage.
It'll finish.
chmodme